Ssd help needed.

Short answer, yes with its 400MB/s SSD speed, it will serve as a capable boot drive, and it even ships with the USB3 cable.

 

You CAN boot and run a Mac Mini from an SSD mounted in a USB3 enclosure.

It will run as fast as an internally-installed drive. You will be VERY happy with the results.

I would like to offer a suggestion:
You can also put together an "external booter" yourself, that will be as good as or better than purchasing a "pre-assembled" drive.

All you need is the right enclosure, like this:
http://www.amazon.com/Optimized-Ina...1138314&sr=8-1&keywords=inateck+usb3+2.5+uasp
(I'm not sure if this is available in the UK)

Then, just buy the "bare" SSD of your choice and "drop it in". You don't even need screws with the above enclosure.
If you can put batteries into a remote control, you can assemble the enclosure above. Just slip off cover, drop drive in, replace cover, done.

The "price point" for SSD's seems to be coming down now. I've seen good values at the 240gb level, and decent buys at the 480gb level.

Important:
For an "external booter", you need an enclosure that supports something called "UASP" (USB attached SCSI protocol). This feature enables the drive to run at the highest speeds capable (5gb per second).

Also:
The big advantage of "building your own" drive, is that YOU buy the parts, YOU put it together, so if there's ever a problem, you know what's inside and you know how to take it apart.

ANYONE can do this (if I did, you can too).